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Moving Quick Today… General Psychology Scripture • Matthew 5:4 Blessed are those who mourn, for they will be comforted. They that mourn - Either for their own sins, or for other’s, and are steadily and habitually serious. They shall be comforted - More solidly and deeply even in this world, and eternally in heaven. • Say the colors as fast as you can. It is not as easy as you might think! • Can you do it faster with practice? • This is called the stroop effect* Words may process faster than colors. Interconnection of Culture and Brain Processing Searching for the self by studying the body Phrenology Phrenology (developed by Franz Gall in the early 1800’s): the study of bumps on the skull and their relationship to mental abilities and character traits Phrenology yielded one big idea-that the brain might have different areas that do different things (localization of function). Today’s search for the biology of the self: biological psychology Biological psychology includes neuroscience, behavior genetics, neuropsychology, and evolutionary psychology. All of these subspecialties explore different aspects of: how the nature of mind and behavior is rooted in our biological heritage. Our study of the biology of the mind begins with the “atoms” of the mind: neurons. Neurons and Neuronal Communication: The Structure of a Neuron There are billions of neurons (nerve cells) throughout the body. Action potential: a neural impulse that travels down an axon like a wave Just as “the wave” can flow to the right in a stadium even though the people only move up and down, a wave moves down an axon although it is only made up of ion exchanges moving in and out. Parts of a Neuron Cell Body: Life support center of the neuron. Dendrites: Branching extensions at the cell body. Receive messages from other neurons. Axon: Long single extension of a neuron, covered with myelin [MY-uh-lin] sheath to insulate and speed up messages through neurons. Terminal Branches of axon: Branched endings of an axon that transmit messages to other neurons. When does the cell send the action potential?... when it reaches a threshold The neuron receives signals from other neurons; some are telling it to fire and some are telling it not to fire. When the threshold is reached, the action potential starts moving. Like a gun, it either fires or it doesn’t; more stimulation does nothing. This is known as the “all-ornone” response. The threshold is reached when excitatory (“Fire!”) signals outweigh the inhibitory (“Don’t fire!”) signals by a certain amount. How neurons communicate (with each other): The action potential travels down the axon from the cell body to the terminal branches. The signal is transmitted to another cell. However, the message must find a way to cross a gap between cells. This gap is also called the synapse. Threshold Threshold: Each neuron receives excitatory and inhibitory signals from many neurons. When the excitatory signals minus the inhibitory signals exceed a minimum intensity (threshold) the neuron fires an action potential. Action Potential Properties All-or-None Response: A strong stimulus can trigger more neurons to fire, and to fire more often, but it does not affect the action potentials strength or speed. Intensity of an action potential remains the same throughout the length of the axon. Refractory Period & Pumps * Refractory Period: After a neuron has fired an action potential it pauses for a short period to recharge itself to fire again. Negative Ions enter. * Sodium-Potassium Pumps: Sodium-potassium pumps pump positive ions out from the inside of the neuron, making them ready for another action potential. Experiment Need 10 volunteers… You need to be willing to have your toe touched and to touch a toe. Action Potentials have to travel. The Synapse The synapse is a junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The synapse is also known as the “synaptic junction” or “synaptic gap.” Neurotransmitters Neurotransmitters are chemicals used to send a signal across the synaptic gap. Reuptake: Recycling Neurotransmitters [NTs] Reuptake: After the neurotransmitters stimulate the receptors on the receiving neuron, the chemicals are taken back up into the sending neuron to be used again. Neural Communication: Seeing all the Steps Together Neural Communication Acetylcholine [ah-seat-el-KO-leen] a neurotransmitter that, among its functions, triggers muscle contraction Endorphins [en-DOR-fins] * “morphine within” natural, opiatelike neurotransmitters linked to pain control and to pleasure Roles of Different Neurotransmitters Some Neurotransmitters and Their Functions Neurotransmitter Function Problems Caused by Imbalances Serotonin Affects mood, hunger, sleep, and arousal Undersupply linked to depression; some antidepressant drugs raise serotonin levels Dopamine Influences movement, learning, attention, and emotion Oversupply linked to schizophrenia; undersupply linked to tremors and decreased mobility in Parkinson’s disease and ADHD Acetylcholine (ACh) Enables muscle action, learning, and memory ACh-producing neurons deteriorate as Alzheimer’s disease progresses Norepinephrine Helps control alertness and arousal Undersupply can depress mood and cause ADHD-like attention problems GABA (gammaaminobutyric acid A major inhibitory neurotransmitter Undersupply linked to seizures, tremors, and insomnia Glutamate A major excitatory neurotransmitter; involved in memory Oversupply can overstimulate the brain, producing migraines or seizures; this is why some people avoid MSG (monosodium glutamate) in food Serotonin pathways Networks of neurons that communicate with serotonin help regulate mood. Dopamine pathways Networks of neurons that communicate with dopamine are involved in focusing attention and controlling movement. Hearing the message How Neurotransmitters Activate Receptors When the key fits, the site is opened. Keys that almost fit: Agonist and Antagonist Molecules An agonist molecule fills the receptor site and activates it, acting like the neurotransmitter. An antagonist molecule fills the lock so that the neurotransmitter cannot get in and activate the receptor site. The Inner and Outer Parts of the Nervous System The central nervous system [CNS] consists of the brain and spinal cord. The CNS makes decisions for the body. The peripheral nervous system [PNS] consists of ‘the rest’ of the nervous system. The PNS gathers and sends information to and from the rest of the body. Types of Neurons Sensory neurons carry messages IN from the body’s tissues and sensory receptors to the CNS for processing. Motor neurons carry instructions OUT from the CNS out to the body’s tissues. Interneurons (in the brain and spinal cord) process information between the sensory input and motor output. The “Nerves” are not the same as neurons. Nerves consist of neural “cables” containing many axons. Nerves are part of the peripheral nervous system and connect muscles, glands, and sense organs to the central nervous system. More Parts of the Nervous System The Peripheral Nervous System The Autonomic Nervous System: The sympathetic NS arouses (fight-or-flight) The parasympathetic NS calms (rest and digest) The Central Nervous System The brain is a web of neural networks. The spinal cord is full of interneurons that sometimes have a “mind of their own.” Neural Networks These complex webs of interconnected neurons form with experience. Remember: “Neurons that fire together, wire together.” Interneurons in the Spine Your spine’s interneurons trigger your hand to pull away from a fire before you can say OUCH! This is an example of a reflex action. Pupil to Pupil • Turn to a partner and have them close their eyes for five seconds and then open them. • What happens to their pupil? • Why? How Fast are You? • Hold the ruler near the end (highest number) and let it hang down. Have another person put his or her hand at the bottom of the ruler and have them ready to grab the ruler (however, they should not be touching the ruler). Tell the other person that you will drop the ruler sometime within the next 5 seconds and that they are supposed to catch the ruler as fast as they can after it is dropped. Record the level (inches or centimeters) at which they catch the ruler. Test the same person 3 to 5 times (vary the time of dropping the ruler within the 5 second "drop-zone" so the other person cannot guess when you will drop the ruler).